A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Effect of illumination on magnetization and microwave absorption of La1-xCaxMnO3 (x < 0.2) films
Tekijät: Huhtinen H, Laiho R, Vlasenko LS, Vlasenko MP, Zakhvalinskii V, Leiro J, Mattila S, Sutara F, Vondracek M
Kustantaja: ELSEVIER SCIENCE BV
Julkaisuvuosi: 2008
Lehti:: Journal of Magnetism and Magnetic Materials
Tietokannassa oleva lehden nimi: JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
Lehden akronyymi: J MAGN MAGN MATER
Vuosikerta: 320
Numero: 11
Aloitussivu: 1747
Lopetussivu: 1752
Sivujen määrä: 6
ISSN: 0304-8853
DOI: https://doi.org/10.1016/j.jmmm.2008.01.038
Tiivistelmä
Light-induced changes of the hysteresis loops of magnetization and microwave absorption are investigated in low-doped La1-xCaxMnO3 (x<0.2) thin films. The width of the hysteresis loops decreases clearly under illumination with visible or near-infrared light at temperatures below 50 K. The microwave conductivity has a minimum value at magnetic fields corresponding to the magnetization reversal and is shifted towards weaker fields under illumination. These effects show complex nonexponential time evolution and dependence on strength of the magnetic field. The results can be explained by assuming that small ferromagnetic metallic regions exist within the insulating ferromagnetic phase of the sample, and that these regions are expanded by optically induced charge transfer between Jahn-Teller split e(g) states of neighboring Mn3+ ions. Decrease of the Mn3+ XPS core level spectrum is observed in the samples under illumination with a HeNe laser. (C) 2008 Elsevier B.V. All rights reserved.
Light-induced changes of the hysteresis loops of magnetization and microwave absorption are investigated in low-doped La1-xCaxMnO3 (x<0.2) thin films. The width of the hysteresis loops decreases clearly under illumination with visible or near-infrared light at temperatures below 50 K. The microwave conductivity has a minimum value at magnetic fields corresponding to the magnetization reversal and is shifted towards weaker fields under illumination. These effects show complex nonexponential time evolution and dependence on strength of the magnetic field. The results can be explained by assuming that small ferromagnetic metallic regions exist within the insulating ferromagnetic phase of the sample, and that these regions are expanded by optically induced charge transfer between Jahn-Teller split e(g) states of neighboring Mn3+ ions. Decrease of the Mn3+ XPS core level spectrum is observed in the samples under illumination with a HeNe laser. (C) 2008 Elsevier B.V. All rights reserved.
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